In the field of data storage, enterprises have used a variety of techniques in order to store the data that their software applications use. At one point in time, each individual computer server within an enterprise running a particular software application (such as a database or e-mail application) would store data from that application in any number of attached local disks. Although this technique was relatively straightforward, it led to storage manageability problems in that the data was stored in many different places throughout the enterprise.
These problems led to the introduction of the storage area network in which each computer server within an enterprise communicated with a central storage computer node that included all of the storage disks. The application data that used to be stored locally at each computer server was now stored centrally on the central storage node via a fiber channel switch, for example. Although such a storage area network was easier to manage, changes in computer server architecture created new problems.
With the advent of virtualization, each computer server can now host dozens of software applications through the use of a hypervisor on each computer server and the use of virtual machines. Thus, computer servers which had been underutilized could now host many different server applications, each application needing to store its data within the storage area network. Weaknesses in the storage area network were revealed by the sheer number of server applications needing to access disks within the central storage node.
For example, the same application executing on different hypervisors (whether on different computers or not) is required to use the same target virtual machine (under the iSCSI protocol) when accessing a particular virtual disk. This causes latency issues and may cause a computer or virtual machine to crash. Improvements are needed in order to provide greater efficiency and to ensure continual access to storage data in the cloud by remote applications.